Oil-burner control



Aug. 17 1926.

J., B. HOFF OIL BURNER CONTROL Filed April 15, 1926 2 Sheets-Sheet 1 Patented Aug. 17,1926.

"UNITED STAT Joann: TB. HOFF, or rn'mAnELPHLA, PENNsYLvANIL OIL-BURNER CONTROL.

Application filed April 13, 1926'. Serial at. 101,665.

My invention relates to new and useful improvementsin an oil burner control, and more particularly to safety controls for automatic liquid fuel or oil burners, and'has for its primary object to provide adevice of this character which will prevent the burner starting prior to Ignition taking place.

provide a safety control which;

l. Prevents the burner from starting in case the ignition should fail.

2. Prevents the burner. from' starting should the spark coil, magnet or other ignition device. fail to function;

3. Prevents the burner from starting should the spark ga become shorti-circuited or the ignition cab e become groundedor short-circuited.

4Q Prevents the even though it is shut off only for an instunt by interruption of electric current or from other cause, .until ignition has again aken place.

5. Prevents the burner from starting without the electric spark jumping at the spark gap as intended.

6. Prevents the burner from starting should the electric spark jump at any other 1 place except at the point set for proper ignition.

7. Prevents the starting of the burner should any one of the devices used in the entire system fail to function. I

8. Prevents the starting of the burner should any wire or connection in'the entire system become disconnected or broken.

Other objects of the invention a e to provide a. safety control device which starts the burner from the efi'ect attained from actual 'nition being supplied at the proper point for igniting fuel in the combustion chamber or furnace; one that is not afiected by the refractory heat in the furnace; which shuts oil the burner should the fuel supply fail, in which case the safety control must be manually reset before the burner can be started; which operates on either straight electric or electric and gas ignition; andwhich absolutely eliminates the injection of fuel into the furnace it said fuel is not ignited.

lVith these ends in view, this invention consists in the details of construction and combination of elements herihafter set A further object of the invention is tocontrol switches relative to the burner.

I burner iron 1 a known as a stack switch'which must also forth and then specifically designated by the claims.

In order that-those skilled in the art to which this invention appertains, may understand how to make and use the same, I will describe its construction in detail, referring by numerals to the accompanying drawings forming a part of this application, in which:

Fig. 1,. is a diagrammatic View 0 the sev-" eral circuits and parts used'to me. 'e up the control;

Fig. 2, is an end view of. a thermostatic controlled mercury tube switch shown with in a housing, the cover of which has been removed;* I I Fig. 3, is a sectional view thereof;

Fig. 4, is a view similar toFig. 2; show--' ing the relation of one of these thermostatic- All automatic liquid fuel or oil burning systems are equipped with room thermostats All of in connection with the system utilizing my safety control. Many liquid fuel burners; use what is able conductor leading from asource of electrical energy to a conductor 6 connected 9 with'a contact 7 in a tiltahle mercury tube;

switch 8, and the tube of this. switch also has another contact point 9 from which. leads a conductor 10 to another conductor 11 which in turn is connected withanot-her loov conductor 12 attached to a contact 13, pref-' erably or" the two point type, so that one of its points M is at one end of the mercury tube switch 15, while the other point 16 is at the other end of said tube. point 14 is associated with the contact 17- from which leads a conductor 18, the latter being-connected with a conductor 19 running to the magneticvignition valve 20 for controlling the flow of gas through the ig- 119 The contact 0 nition tube 21 terminating adjacent the nozzle 22 of the burner 23 including an oil feed pipe 24 leading to thenozzle.

In order to complete the circuit partially described above, the conductor 25 leads from the magnetic ignition valve 20 to a heating coil 26 of a .bi-metallic thermostat 27 which includes the thermostatic element 28 mounted upon the adjustable bracket 29 and provided with a stem 30 in cooperative relation to the tiltable table 31 pi votedat 32 and on which the tube of the mercury switch is mounted. From the heating coil 26 leads a conductor 33 connected to a con- .ductor 34 which, in turn, is connected with similar instrument 37, the latter being connected b a conductor 38 with the other pole of t e source of electrical energy, opposite to the one connected by the conductor 5.

An associated or branch circuit includes a conductor 39 leading from the conductor 19 to one side of the spark coil or other ignition device 39, such as a motor driven magneto, transformer and the like, while the other side of theignition device is connected byg a conductor 40 with conductor 25, thus ma ing up the primary circuit forv the ignition device. The secondary of the ignition device is conventionally represented by a conductor 41 leading) from the spark coil 'to a portion of'the one of the electrodes and ground, with which is associated an electrode 42 connected by a conductor 43 with the spark coil- Another circuit associated with the first one includes -a conductor 44 leading from the conductor 19 to a contact 45 mounted in the tube of the mercury tube switch- 46,

with this contact is associated another contact 47 from which leads a conductor 48,

the latter being connected to a conductor.

49 which, in turn, is connected with one pole of theelectro or lifting magnet 50, while the other pole thereof is connected by a conductor 51 with conductor 25.

' i able automatic switches in their circuits.

i'irnernozzle, as

washer 59 and spring 60, so that under cer-' tain conditions the rod may slip or rotate withoutnctuating the fork, which may be limited' in' its movements by the stops 61' and 62. 'In the arms of the fork are mounted suitable set screws 63 for coaction.

with the depending leg 64 of the tiltable table 65 which holds the mercury tube switch 46.

From the above, it will be obvious that when the helix moves, due to a chan e in temperature, the rod 56 will be rotate and the 'fork 58 will be oscillated in order to transmit'motion to the dependingleg 64 and tilt the table 65 in one direction or the cuits 'terminatingin the mercury tube.

Associated with the lifting magnet 50 is an armature 66 pivoted, as at 67, and having its free end projecting into the space between the arms 68 of the fork at the end of the tiltable table 69 carrying a mercury tube switch 70. -In the tube of this switch is a contact 71 connected by a conductor 72 with a conductor 78 leading to the contact 74 in the end of the mercury tube switch 46 opposite conconductor 11 so that connection is made with' one side of the source of electrical energy; In the tube of the mercury tube switch 7 O is another contact 78 connected by "a conductor 79 with the conductor 80 leading to the electro or holding magnet 81, and from this magnet leads a conductor 82 to one pole of the motor 83, while the other, pole.

thereof is connected by a conductor 84 with the conductor 34 and therefore the other side of the source of electrical energy.

Another :circuit is formed by the use of-a contact 85 connected by a conductor 86 withthe conductor 87 which, in turnis connected with the conductor 72 leading to the contact 71; the other side of this circuit being completed through the holding magnet 81 and motor 83 previously described.

When heat or pressure is required, the

thermostat, hydrostat andpressurestat are closed, and therefore the current is flowing through the safety switch 18, and if thisswitch is in the position shown in Fig. 1 so that the mercury closes the circuit'between the contacts 7 and 9, said current will flow I "through the contacts 1.4 and 17 of the stack few degrees below the temperature of saidheater when the burner stopped, thence through the liftingmagnet 50 and the ignition control switch 46 and through the mag switch 15, providing the heater is cold or a netic ignition valve 20' and the ignition device 39, such as a spark coil, motor driven magneto, transformer or the like, and thence through the heating coil 26 and the afore mentioned hydrostat or the like and thermostat, ther,eby completing a circuit and its branches. The current flowing through the tol flow through the valve to the. ignition point at the nozzle of the burner. Simultaneously with the opening of the ignition valve the electric ignition is set into operation causing the spark to jump at. the end of the gas pipe 21 which lies adjacent the burner nozzle, thereby igniting the gas or an equivalent substance, such as alcohol, which is flowing through the pipe 21. At the same time a certain amount of the gas will'flow through the pipe 52 and out of its perfora tions where said gas will be ignited and produce aflame along the'pipe 52, and the heat generated directly under the helix or spiral 53 causing the latter to expand and actuate the armature 58 so as to tilt themercury switch 46, thereby closing a circuit which includes the contacts 74 and 75 which there- 'fore completes the circuit through the holding magnet 81 and the motor 83, and it is -to be understood that the holding magnet may be wound for connecting it with the motor, either in series or parallel without aflecting the working of the system. The

ignition being in working order, the motor will start and deliver the fuel just after the ignition has been placed in operative condition. 'It will be obvious that if ignition had not taken place, the helix or spiral would haireiemainedin its normal condition, and

the switch 46 would not have beenoperated,

and therefore the motor could not have been started. I

r The ignition having taken place, should therebe nofuel delivered by the motor, the

current will continue to flow through the I heating coil 26,'and shortly cause the asso-- ciated thermostat 28- to actuate the safety switch 8, so that it will be tilted to a position be opposite that shown in Fi 1, thereby opening the several circuits an causingthe magnets to be deenergized, so as to release the armature 66 which'i-will open the switch 70,

and at the same time, the gas valve 20 will be closed and the ignition shut off permitting the helix or spiral 53 to cool down-until the switch 46 assumes its normal the heating coil 26 has coo ed down sufiiciently, the switcli'S'may be-again manually osition. After 7 closed placing the system incondition for I further operation.

r If, however, fuel is delivered to the nozzle of the burner, and it is ignited, the heat from the furnace passing up the smoke pipe or stack will cause the stack switch 15 450 be actuated in the same manner as the switch 46 for said switch 1 5 is also provided with a helix or spiral rheostat 'or an equivalentactuating means. Theswitch '15 being tilted tothe position opposite that shown in Fig. 1 by the heat in'the stack,-as above stated, the' circuit is completed throughconductbrs 5 and 6, safety switch' 8, the stack switch 15- by means of itscontacts 16 and 85,'tl1'ence through-the conductors 86,'87, 72'and the con-; tact 71, the switch 7 0, contact'78; conductors; 7 9 and 80, holding magnet 81,- conductor-82, motor 83, conductors 84 and '34, the controlling element 35, conductor 36, controlling eleof the-source of electrical current."

ment 37 and conductor 38 to the other-side all:

As the 'last mentioned circuit isclosed,"

the operation of thesafety switch 15 opens the circuit or circuits, through the valve 20, the liftingmagnet 50'and the i vice ,39, thereby cutting ofl t 086}? parts which areno 'further needed, until it ,,be-

comes necessary to-restaft the burner. Should the main suppl of electric, cur

rent beinterrupted, even or an instant, the holding magnet 81 will be deenergized,

thereby dropping the armature 66' which will open a switch 70, thereby cutting oil I the current to the motor 83, andfthis switch 70 will remain in this osition until the temperature ofthe stack rops sufliciently to tilt the stack switch 15 to the position shown in Fig. 1, when the ignition cycle can be repeated-and the burner again started.

noted that the switch 46 From the foregoing descri tion it will eing operated from heat generated by the ignition spark and gas, or ignition spark and alcohol, as the "case may be, eliminates any possibility of the burner starting until ignition actually takesplace; and as the operations of the magnets depend upon this-heat enerated from the ignition, it follows that t e motor cannot be started until ignition has taken place, and cannot continue to operate unless a steady flow or current is assing through the motor so as to operate the latter. Further, it.wi1l be noted that should the burner extinguished," or what is commonly known as the flame leaving the burner, the temperature of the stack will decrease, and therefore the switch 15 will be moved from the running position toithe startingposhv tion, as shown in Fig. 1, and the motor will be stopped until ignition has again taken lace.- v i? ll- After 'fullycomprehending" the scope of Lion, it will beobvion'sthat 'atnoftime can. a large quantity of i fuel Ebe' delivered to the furnace; without being ignited; thereby""re'- duuing to a minimum, if ii'otentirely, elinisaid switch 'under certain conditions-, a hea't'' ing coil for actuating the thermostat, a burner and ignition, device for-said bil rner', an electrically actuated valve to'supply-th'e ignition device with a-suitnble burnabie sub-' stance, a spars: producing means, =a=double switch,.moans .to 1 open one side: of said switch and close the other side thereofdue to heat generated by the lgmtloni device; a hfung magnet, a'holdmg magnet, swarms-- 4 tnre associated with said magnets,"a switch actuated by said armature to partially close a circuit throu h .the'holding magnet and the motor of t 0 oil burner and a 'double stak switch, operable from jhegt vnithin,..,a- 3

holding in'dgnetfandmotor isQpoxnPletedfnd h i' fi'"t esglii he. in magn t, the p kir fi 'ng biirn'er cont fol iiicliidiiiglen igninjo'n.

' nieans theifino' and preslsn e I control means 1n .'"m9 91 a d .l pt ma y actuate mechanisms to plaw'the the the'rmdi 'prs'sui ef regnleting means a i Pn .v to'start' the Inotoit1i1*to"hest generated by said ignition means.

3i'j'1he 'combiii'zit'ion wit miner kind a. s

motor' for supplying fuel to saidbnrner; of an ignition means'essociited with said burnan; m en-1 15 for placing the ignition. means in operative condition; 'means responsive to the ignition mei n's" tifsta rt' the motor; other means responsive means" for, fontting efibe andfv'a-Iyeis opened,

onsiye to' the ignition means 'ont th ignition means whi1e retziiiiing""*themotor.in running con-.

diti'on and xi iiothr' means responsive to h'egit genriit''ci by thebulnei foii'fontrolling saidJothenz'nearis.

*In' testimony where f; fixd iny sign'qtnre';

JOSEPH I 

